rtl-ppa-optimize-dc

Execute ONE iteration of the DC-based PPA optimization loop against a verified RTL design. Produces `docs/ppa-opt/iter-{N}/` with the synthesis reports, RTL patch, equivalence/smoke evidence, and a convergence verdict. For automated iteration until convergence, use `rat-ultraloop-ppa` instead.

<Use_When>

• User says "PPA optimize", "DC PPA", "power/timing/area optimize"
• A single exploratory PPA iteration is desired
• Debugging the PPA loop mechanics without auto-continue </Use_When>

<Do_Not_Use_When>

• Phase 5 verification has not passed (use rtl-p5-verify first)
• No dc_shell nor genus available (this skill hard-fails)
• Full automatic iteration is wanted (use rat-ultraloop-ppa)
• RTL still under active development (finish Phase 4 first) </Do_Not_Use_When>

Prerequisites

• reviews/phase-5-verify/final-compliance.md verdict=PASS (soft advisory — warns and proceeds if absent)
• dc_shell OR genus in PATH (HARD — fail on absence)
• requirements.json["ppa_targets"] populated (HARD — writeback scaffold and halt)
• Git working tree clean under allowed_edit_scope (no uncommitted changes AND no untracked files in rtl/${PPA_TOP} — untracked files would be silently deleted by rollback git clean -fd)
• syn/scripts/run_syn.sh deployed by rat-init-project

Invocation

/rtl-agent-team:rtl-ppa-optimize-dc [top_module]

When top_module is omitted, reads from requirements.json["top_module"].

Execution

# Step 1: Bootstrap ppa-loop-state.json if absent
if not exists(".rat/state/ppa-loop-state.json"):
    Write(".rat/state/ppa-loop-state.json", initial_state(
        target_module=ARGUMENTS or requirements.top_module,
        max_cycles=requirements.ppa_targets.convergence.max_cycles or 4
    ))

# Step 2: Check preconditions (fail fast)

# Validate PPA_TOP: must be a non-empty, strict SV identifier
PPA_TOP="${ARGUMENTS:-$(python3 -c 'import json; print(json.load(open("requirements.json"))["top_module"])' 2>/dev/null)}"

if [ -z "${PPA_TOP}" ]; then
    echo "ERROR: PPA_TOP must be provided via argument or requirements.json['top_module']" >&2
    exit 1
fi

# Reject any PPA_TOP that is not a plain identifier — prevents shell injection
# and the 'empty scope wipes rtl/' footgun when PPA_TOP expansion defaults.
case "${PPA_TOP}" in
    *[!A-Za-z0-9_]*|[!A-Za-z_]*)
        echo "ERROR: PPA_TOP='${PPA_TOP}' must match [A-Za-z_][A-Za-z0-9_]* (no shell metachars, no path segments)" >&2
        exit 1
        ;;
esac

# Validate PPA_LIBERTY and PPA_SDC paths — reject shell AND Tcl metachars, must be existing regular files.
# Note: Tcl evaluates [...] as command substitution inside double-quoted strings, so [ ] \ must also
# be rejected even after shell quoting (Codex R2 H1).
for _var in PPA_LIBERTY PPA_SDC; do
    _val=$(eval "printf '%s' \"\${$_var:-}\"")
    if [ -z "${_val}" ]; then
        continue   # unset is OK; orchestrator checks specifics later
    fi
    case "${_val}" in
        *[\`\$\;\&\|\<\>\"\'\ \[\]\\]*)
            echo "ERROR: ${_var}='${_val}' contains unsafe shell/Tcl characters (one of \` \$ ; & | < > \" ' space [ ] \\\\)" >&2
            exit 1
            ;;
    esac
    if [ ! -f "${_val}" ]; then
        echo "ERROR: ${_var}='${_val}' is not a regular file" >&2
        exit 1
    fi
done

assert shutil_which("dc_shell") or shutil_which("genus"), \
    "Commercial synthesis (dc_shell or genus) required"

# Hard precondition: no uncommitted changes AND no untracked files in allowed_edit_scope
if [ -n "$(git status --porcelain -- rtl/${PPA_TOP})" ]; then
    echo "ERROR: working tree must be clean under rtl/${PPA_TOP} (commit or stash first)" >&2
    exit 1
fi
# Note: Untracked files within `rtl/${PPA_TOP}` MUST be committed or removed before
# starting — otherwise rollback `git clean -fd` would delete them silently.

# Step 3: Advance cycle counter
state.cycle += 1
Write(".rat/state/ppa-loop-state.json", state)

# Step 4: Dispatch orchestrator (it writes Rule 5 marker unconditionally on convergence)
Task(subagent_type="rtl-agent-team:ppa-optimizer-dc-orchestrator",
     description=f"PPA iteration {state.cycle}",
     prompt="Execute one PPA optimization iteration. Read .rat/state/ppa-loop-state.json for scope and history.")

Do not perform per-iteration work directly. The orchestrator handles all synthesis / parsing / patching / equivalence / convergence.

Completion

The skill reports the verdict returned by the orchestrator. If verdict is CONVERGED_STREAK or CONVERGED_TARGETS:

• Write .rat/state/rtl-verify-done (Rule 5 satisfaction marker — orchestrator also writes this idempotently; both writes are safe)
• Recommend running rtl-p5-verify for full regression confirmation

NOTE: The one-shot skill does NOT emit ppa-opt-done. To declare true convergence (and trigger Phase 6 cascade re-review), use rat-ultraloop-ppa which runs the mandatory final /rtl-agent-team:rtl-p5-verify --mode=final --source=ppa-opt regression before writing ppa-opt-done.

Otherwise, the skill returns the verdict and exits. For CONTINUE, the user invokes again or switches to rat-ultraloop-ppa.